大鼠钳夹脊髓损伤模型的磁共振影像与感觉诱发电位的相关研究

Correlation Between MRI Characteristics and SEPs on Rat Model of Clip Compression for Spinal Cord Injury

使用磁共振成像(magnetic resonance imging,MRI)与感觉诱发电位(somatosensory evoked potentials,SEPs)连续性评估大鼠脊髓钳铗钝性损伤模型的影像学与神经电生理的变化.16只SD大鼠建立脊髓钳铗钝性损伤模型,其中假手术组8只,脊髓损伤组8只,术后6 h、1 d、3 d、7 d、14 d、21 d、28 d使用MRI及SEPs对受损脊髓情况进行连续性评估.发现术后脊髓损伤组SEP图形显示:术后6 h、1 d、3 d未引出波形(潜伏期与波幅均为0);术后7 d、14 d、21 d、28 d均能引出波形,随术后时间的延长,诱发电位潜伏期逐步降低、波幅增大;假手术组与脊髓损伤组各个时间点对比,均有差异(P<0.05).术后脊髓损伤组MRI显示:术后6 h胸段脊髓创伤部位呈局限性点状T2WI高信号影;术后1 d至3 d胸段脊髓肿胀,损伤处及尾端脊髓呈大片状T2高信号改变;术后7 d至14 d,胸段脊髓内片状T2WI高信号区范围缩小;术后21 d至28 d,胸段脊髓内仅有小片T2WI高信号影,脊髓远端直径较正常明显缩小.假手术组在各时间点脊髓MRI均无明显改变.总之该模型稳定、可靠;通过SEP,MRI动态观测,对该模型脊髓损伤后的病理生理转归做客观评价,为该模型进一步研究脊髓损伤提供有效的动物实验数据.

MRI and SEPs are employed to evaluate the changes of the blunt spinal cord injury rat model in iconog- raphy and nerve eleetrophysiology. Both changes of the sham -operation group （n = 8） and the spinal cord injury group （n =8） are examined by MRI and SEPs at 6 h, 1 d, 3 d, 7 d, 14 d, 21 d, 28 d respectively after the post- operation. It is found that the SEPs show a straight line at 6 h, 1 d, 3 d after modeling; On the 7th d, 14th d, 21th d, 28th d of post -operation there are SEPs evoked; The latency reduces with the extension of time, but am- plitude increases; There are differences at each time point in the latency and amplitude between the two groups a- bove （P 〈 0. 05）. MRI of the spinal cord injury group shows ： High - density signal in T2W1 at 6h after operation presents as circumscribed dots; High -density signal presents as a big sheet in T2, from 1st to 3rd day in the post -operation; 7 -14 days later, the boundary of high -density signal obviously decreases; 21 -28 days later, there is only a small sheet left in T2 high - density signal, and the diameter of the far - end of the injury obviously de- creases. At every time point the sham - group rats have no changes in MRI. In short, this model is stable and reli- able. Through dynamic observation by the SEP and MRI, an objective evaluation of the physiopathologic changes of spinal cord injury provides some effective data about animal experiment for further study.